Carburetor



P 1944. 'r. M. BALL CARBURETOR Original Filed July 29, 1940 INVENTOR Tfiamaa' Law 22%;. ATTORNEY5.

Patented Sept. 19, 1944- Thomas M. Ball, Detroit, Mich, 'assignor, by mesne assignments, to Chrysler Corporation,

Highland Park,

ware

Micln, a-corporation'of- Dela- 4 Original application JulyY29, 1940,; Serial No. 348,095. Divided and this application February 9, 1942, Serial No. 429,997

1 Claim. (01.- zen-2s) The present invention relates to the idling adjustment of a dual throat carburetor for internal combustion engines, and this application is a division of my co-pending application Serial No.

348,095,11166. July 29, 1940. Dual throat carbu retors are in commonuse today and comprise a unit consisting of two carburetor devices under the control of a-single set" of throttleand choke devices. The usual practice in such dual throat carburetors is to provide a separate idle adjustment for each throat, and in'practice' it has been found extremely difiicult, if not impossible, to regulate each idle adjustment to the same extent so that uneven firing of the engine controlled thereby results; It is the principal object of the present invention to place regulation of the idle discharge of the two throats of a dual throat carburetor under control of a single adjusting screw in order that exactly the same fuel and air mixture may be fed to each throat during idling operation of the engine.

An object of the present invention is to provide means whereby the regulation of idling is achieved by adjustment of a single valve controlling the amount of air mixed with the fuel, which valve is adjacent the transfer and idle ports of a carburetor having such ports, and being so positioned as to control the richness of mixture when the engine is idling.

The invention has for its object the provision of 'means whereby the single adjustment screw admits more air on idling than on transfer action so as to provide for the admission of a richer mixture when transferring to higher speeds without altering the idle adjustment,

The objects and advantages of the present invention should be more readily understood from the following specification taken in connection with the accompanying drawing which sets forth preferred embodiments I of the invention and wherein like numerals refer to like parts throughout.

In the drawing,

Fig. l is a partially cut-away view in elevation of a dual throat carburetor having a form of the present invention applied thereto;

Fig. 2 is a vertical section taken substantially along line 22 of Fig. 1 and looking in the direction of the arrows;

Fig. 3 is a partially cut-away view in elevation of the lower end of a dual throat carburetor embodying the invention;

Fig. 4 is a section taken substantially along line 4--4 of Fig. 3 and looking in the direction of the arrows; and

,Fig, '5 is a vertical section takensubstantially along line 5 '5 of Fig. 3 and looking in thedirectionof the arrows. V I

. The present invention is applied to a dual throat carburetor I0 having the usual air inlet I I and choke device I2 under'control of the usual choke operating mechanism. The carburetor is providedjwith a plurality of fuel inlet reservoirs I3 peach. of which feeds fuel into an associated throat. I4 through the usual fuel inlet nozzle I5 and nozzle inlet I6. Fuel is sucked thIOllghthi-E inlet l6 and .nozzle I5 by the rush of air through ajVenturl device broadly designated at H. In-

corporated in the inlet nozzle construction is a well I8 from which extends vertically an idle snatcher tube I9 having an outlet communicating with an idling passage I20 leading downward to the. vicinity of the throttle valve 2|. Fuel is admitted to the idling passage I20 from the idle snatcher tube I9 by the aspirating effect of air drawn from the air inlet II through an opening 22 at the upper end of the idling passage I20, which movement of air is induced by the engine suction on the fuel jet I23 which is located below the throttle valve 2I. A transfer port I24 opens into the throat I4 above the throttle valve 2I when in closed position from the idle passage I20 for the purpose of admitting fuel mixture to thetransfer ports to feed fuel mixture to the enginein greater amount than required for idling prior to the time that the main inlet becomes effective it is desirable to increase the suction on the idle snatcher tube I9 at this moment. Figs. 3, 4, and and 5 disclose an embodiment of the invention whereby this result is achieved. In these figures it is apparent that the mixture regulating passage I30 is so arranged as to extend between the individual idle inlet ports I23 which are placed at the junctions of the idle fuel inlet tubes I20 and the passage I30. The central portion of the passage I30 is provided with a Valve seat in which is placed the needle point of a needle valve I3I provided with a spring take-up device I32, the needle valve seat extending from the passage I30 to a vertical air inlet passage I40 leading from an air horn I4I communicating with the outside atthrough the .air horn mosphere. Regulation of the needle valve I3I regulates the amount of air which passes into the passage I30 for admixture with the fuel mixture passing through the idle inlet ports I23, whereby equal and simultaneous adjustment of the fuel mixture during idling operation is achieved.

Between each of the transfer ports I24 and the idle inlet port I23 there is placed a restriction I42. When the throttle valve is in closed position, such as seen in Fig. 2, the fuel mixture, comas come within the scope of the following claim posed of air entering through the inlet from above the venturi, such as inlet 22 of the modification shown in Fig. 1, fuel entering from the idle snatcher tube, and air entering from the transfer ports I24, passes through restrictions I42 to be finally proportioned with air admitted MI and passage I30.

When the throttle valve is slightly opened so as to cause the transfer ports to become effective the richness of the mixture is: increased since the" tendency is for more air to be drawn. throughthe inlet above the venturi, thus increasing the amount of fuel drawn throughthe idle snatcher tube, this increase in fuel being. suchas toin crease the proportion-of fuel to air. ,Someair mightbe drawn back through the restriction. I42

from the idle ports I23, and the air: horn I4I, but.

are considered a part of my invention.

I claim:

A carburetor having a plurality of fuel mixture ducts each adapted to be connected to a different section of an internal; combustion engine and a plurality of carbureting devices each associated with one of said fuel mixture ducts, a throttle valve in each fuel mixture duct, an idling fuel intake device associated with each carbureting device and including an idle inlet tube leading to an'idle inlet port located in the wall of the associated fuel mixture duct effectively on the engine side of said throttle valve when in closedposition whereby the engine suction becomes efiective to draw an idling'mixture through said idle inlet tube during idling operation of the engine; a mixture regulating passage connecting said plurality ofidle inlet tubes, said idle inlet ports being placed at the junctions of said mixture regulating pass-age and said;idle inlet tubes, means to admit auxiliary air into said passage during. idling operation including an auxiliary air inlet passage,- a needle valve insaid auxiliary air inlet passage controlling the amount of air admitted through said meansvduring idling operation whereby the richness of themixtureadmitted through each of said idle inlet ports may be equally and simultaneously adjusted, a transferport connecting each idle inlet tube withone of said mixture ducts respectively at a point on the opposite side of said throttle valve when said throttle valve is in closed position, and a restriction in each idle inlet tube between the transfer port and the idle inlet port associated therewith whereby the richness of the'mixture drawn into said idle inlet tubeis increased during transfer operation.

-. THOMAS M. BALL. 

